public static void ToGrayScale(this ImageMatrix <Color> sourceMatrix, ImageMatrix <byte> targetMatrix)
{
sourceMatrix.Map(targetMatrix, c => (byte)(0.2126 * c.R + 0.7152 * c.G + 0.0722 * c.B));
}
private static Seam GetVerticalSeamOfLowestEnergy(ImageMatrix <byte> energyMatrix, ImageMatrix <int> fitnessMatrix)
{
var height = energyMatrix.Height;
var width = energyMatrix.Width;
// copy first row
for (var x = 0; x < width; x++)
{
fitnessMatrix[x, 0] = energyMatrix[x, 0];
}
// calculate fitness - skip first row
for (var y = 1; y < height; y++)
{
for (var x = 0; x < width; x++)
{
fitnessMatrix[x, y] = energyMatrix[x, y];
if (x == 0)
{
fitnessMatrix[x, y] += Math.Min(fitnessMatrix[x, y - 1], fitnessMatrix[x + 1, y - 1]);
}
else if (x == width - 1)
{
fitnessMatrix[x, y] += Math.Min(fitnessMatrix[x, y - 1], fitnessMatrix[x - 1, y - 1]);
}
else
{
fitnessMatrix[x, y] += Math.Min(fitnessMatrix[x - 1, y - 1], Math.Min(fitnessMatrix[x, y - 1], fitnessMatrix[x + 1, y - 1]));
}
}
}
// get min
var lastRowIndex = height - 1;
var minValue = int.MaxValue;
var minIndex = -1;
for (var x = 0; x < width; x++)
{
if (fitnessMatrix[x, lastRowIndex] < minValue)
{
minValue = fitnessMatrix[x, lastRowIndex];
minIndex = x;
}
}
// get seam
var list = new List <Pixel>
{
new Pixel(minIndex, lastRowIndex)
};
var currentIndex = minIndex;
for (var y = lastRowIndex - 1; y >= 0; y--)
{
var x = currentIndex;
if (currentIndex == 0)
{
if (fitnessMatrix[currentIndex, y] > fitnessMatrix[currentIndex + 1, y])
{
x = currentIndex + 1;
}
}
else if (currentIndex == width - 1)
{
if (fitnessMatrix[currentIndex, y] > fitnessMatrix[currentIndex - 1, y])
{
x = currentIndex - 1;
}
}
else
{
if (fitnessMatrix[currentIndex, y] > fitnessMatrix[currentIndex - 1, y] && fitnessMatrix[currentIndex - 1, y] < fitnessMatrix[currentIndex + 1, y])
{
x = currentIndex - 1;
}
else if (fitnessMatrix[currentIndex, y] > fitnessMatrix[currentIndex + 1, y])
{
x = currentIndex + 1;
}
}
currentIndex = x;
list.Add(new Pixel(x, y));
}
return(new Seam(Direction.Width, list.ToArray()));
}
private static Seam GetHorizontalSeamOfLowestEnergy(ImageMatrix <byte> energyMatrix, ImageMatrix <int> fitnessMatrix)
{
var height = energyMatrix.Height;
var width = energyMatrix.Width;
// copy first column
for (var y = 0; y < height; y++)
{
fitnessMatrix[0, y] = energyMatrix[0, y];
}
// calculate fitness - skip first row
for (var x = 1; x < width; x++)
{
for (var y = 0; y < height; y++)
{
fitnessMatrix[x, y] = energyMatrix[x, y];
if (y == 0)
{
fitnessMatrix[x, y] += Math.Min(fitnessMatrix[x - 1, y], fitnessMatrix[x - 1, y + 1]);
}
else if (y == height - 1)
{
fitnessMatrix[x, y] += Math.Min(fitnessMatrix[x - 1, y], fitnessMatrix[x - 1, y - 1]);
}
else
{
fitnessMatrix[x, y] += Math.Min(fitnessMatrix[x - 1, y - 1], Math.Min(fitnessMatrix[x - 1, y], fitnessMatrix[x - 1, y + 1]));
}
}
}
// get min
var lastColumnIndex = width - 1;
var minValue = int.MaxValue;
var minIndex = -1;
for (var y = 0; y < height; y++)
{
if (fitnessMatrix[lastColumnIndex, y] < minValue)
{
minValue = fitnessMatrix[lastColumnIndex, y];
minIndex = y;
}
}
// get seam
var list = new List <Pixel>
{
new Pixel(lastColumnIndex, minIndex)
};
var currentIndex = minIndex;
for (var x = lastColumnIndex - 1; x >= 0; x--)
{
var y = currentIndex;
if (currentIndex == 0)
{
if (fitnessMatrix[x, currentIndex] > fitnessMatrix[x, currentIndex + 1])
{
y = currentIndex + 1;
}
}
else if (currentIndex == height - 1)
{
if (fitnessMatrix[x, currentIndex] > fitnessMatrix[x, currentIndex - 1])
{
y = currentIndex - 1;
}
}
else
{
if (fitnessMatrix[x, currentIndex] > fitnessMatrix[x, currentIndex - 1] && fitnessMatrix[x, currentIndex - 1] < fitnessMatrix[x, currentIndex + 1])
{
y = currentIndex - 1;
}
else if (fitnessMatrix[x, currentIndex] > fitnessMatrix[x, currentIndex + 1])
{
y = currentIndex + 1;
}
}
currentIndex = y;
list.Add(new Pixel(x, y));
}
return(new Seam(Direction.Height, list.ToArray()));
}
public static void ComputeEnergyMapBySobel(ImageMatrix <byte> grayscaleImageMatrix, ImageMatrix <byte> energyMatrix)
{
var height = grayscaleImageMatrix.Height;
var width = grayscaleImageMatrix.Width;
for (var x = 0; x < width; x++)
{
for (var y = 0; y < height; y++)
{
var p1 = GetPixel(grayscaleImageMatrix, x - 1, y - 1);
var p2 = GetPixel(grayscaleImageMatrix, x, y - 1);
var p3 = GetPixel(grayscaleImageMatrix, x + 1, y - 1);
var p4 = GetPixel(grayscaleImageMatrix, x - 1, y);
var p6 = GetPixel(grayscaleImageMatrix, x + 1, y);
var p7 = GetPixel(grayscaleImageMatrix, x - 1, y + 1);
var p8 = GetPixel(grayscaleImageMatrix, x, y + 1);
var p9 = GetPixel(grayscaleImageMatrix, x + 1, y + 1);
var sobelX = p1 + p2 + p2 + p3 - p7 - p8 - p8 - p9;
var sobelY = p3 + p6 + p6 + p9 - p1 - p4 - p4 - p7;
var sobel = (int)Math.Sqrt(sobelX * sobelX + sobelY * sobelY);
const byte limit = 255;
energyMatrix[x, y] = sobel > limit ? limit : (byte)sobel;
}
}
}
public SeamCarving(ImageMatrix <Color> imageMatrix, ImageMatrix <byte> energyMatrix)
{
ImageMatrix = imageMatrix;
_energyMatrix = energyMatrix;
_fitnessMatrix = ImageMatrixFactory.Empty <int>(energyMatrix.Width, energyMatrix.Height, energyMatrix.OptimizeMode);
}
